Also configure the entry-point for your app's authentication to be the page from which users can login/connect
with a Spring-Social provider (usually a page with a form submit to ProviderSignInController or ConnectController),
and configure an environmental property (socialsignin.signUpView) for a page where user can choose a username
when creating an account which posts a "userId" to the url "/signup" (handled by SpringSocialSecuritySignUpController)

SpringSocialSecuritySignUpController (optional - for handling UI for creating new local accounts - alternative controllers could
be used instead)

SpringSocialSecurityConnectionSignUp (optional - for implictly creating new local accounts. If used, the SpringSocialSecurityJdbcUsersConnectionRepository
must be used in place of standard JdbcUsersConnectionRepository to workaround and issue with JdbcUsersConnectionRepository
not handling null return values from ConnectionSignUp's properly)